Patent Literature 1 discloses a technology for forming a protector around a flat circuit body. The protector is formed by sandwiching the flat circuit body using two covering bodies made of a nonwoven fabric thermoplastic material containing a thermoplastic felt or a foaming agent and press-molding while heating the resulting combination to firmly attach the two covering bodies to the flat circuit body and weld portions of the two covering bodies where they are in contact with each other.